Cutaneous involvement in sarcoidosis. Relationship to systemic disease.

Sarcoidosis is an antigen-mediated disease defined by granuloma formation in different organs. It involves mainly the mediastinal and peripheral lymph nodes, lungs, eyes, skin, liver, and spleen. Cutaneous lesions of sarcoidosis may be specific, showing histologically noncaseating granulomas, or nonspecific, most typically erythema nodosum. Frequently, both types of skin lesions are the means of presentation of the disease and may contribute to the diagnosis. A workup for systemic sarcoidosis should be undertaken in every patient with sarcoid cutaneous granulomas. Some types of cutaneous lesions have prognostic significance. Lupus pernio and plaques are associated with more severe systemic involvement and more chronic course, while erythema nodosum is the hallmark of acute and benign disease.